Health inequality starts long before the doctor

For health demographer Kristina Thompson, this apparent contradiction points to a fundamental problem in the way we think about health. “Health is not just determined by healthcare,” she says. “It is also determined by people’s environments, including social, economic, environmental and commercial factors. If you want to understand what is happening with a person’s health, you need to figure out what is happening all around them.”

That perspective is central to a growing field of social science research at Wageningen University & Research. Instead of asking only how disease can be treated, researchers examine why some groups are more at risk of poor health in the first place, how disadvantages accumulate over a lifetime and how interventions can work through families, communities and social networks.

Differences in health between socio-economic groups are not new, but their scale is. Thompson points to evidence suggesting that differences in mortality between people with high and low socio-economic status have widened since the second half of the twentieth century. Socio-economic status includes factors such as education, income and occupation.

The reasons are complex. One possible explanation is that access to resources has become more consequential for health. Money can buy healthier food, opportunities to exercise and other conditions that support good health. At the same time, chronic diseases have become more important causes of illness and death than infectious diseases, making behaviours such as smoking, diet and physical activity more influential. Those behaviours are themselves socially patterned.

This makes health inequality easy to misinterpret as a matter of individual choice. Thompson’s research challenges that view. Poverty, for instance, is associated with chronic stress. Food choices depend partly on what is affordable and available in a neighbourhood. Education influences opportunities later in life. Housing conditions, employment and social relationships can all affect health. These influences do not occur independently or at a single point in time. They accumulate.

Much health research traditionally relies on a snapshot: a person’s education, occupation or income at a particular age is linked to their health at that moment or later in life. Thompson argues that this can hide much of what is really happening.

A life-course perspective instead looks at how people’s social and economic circumstances develop from childhood onwards. A person’s current education level, for example, may say relatively little about the family they grew up in, the resources they had access to or the social environment that shaped them. “You really need to follow people across their lifetimes to understand their socio-economic status and how it influences health,” Thompson explains.

This is also the starting point for her latest research project “Understanding widening socio-economic inequities in health in the Netherlands. The Dutch government has invested substantially in reducing socio-economic health inequalities, yet the gap has continued to widen. Thompson wants to understand the mechanisms behind that trend more precisely by using long-term and intergenerational data.

The ambition is important because knowing that there are socio-economic differences in health is not the same as knowing how to close the gap. Policies will be more effective if researchers can distinguish between different mechanisms, such as financial insecurity, stress, unequal access to resources or disadvantages that accumulate across generations.

One way to do this is through computational modelling, to simulate how the lives of individuals and populations may develop under different conditions. Rather than only observing what happened in the past, researchers can use such models to explore hypothetical scenarios. What might happen to health inequalities if financial insecurity among families with young children were reduced? Would intervening earlier in life have a greater effect than acting later? What happens when several policies are combined?

This does not turn social policy into an exact science. Human lives are too complex for that, and even very elaborate models are simplifications of reality. But modelling can help researchers make assumptions explicit, compare possible explanations, and identify which interventions are most promising before they are implemented at scale. For Thompson, that is one of the main potential contributions of her current work: moving from knowing that inequality exists towards understanding why it persists.

A second strand of Thompson’s research starts from another simple observation: people do not make health decisions in isolation. A social network consists of the people someone interacts with in everyday life. That can include partners, family members and close friends, but also neighbours, colleagues or casual acquaintances. Even relatively loose relationships can influence behaviour, access to information and a sense of social support.

Research has often focused on how unhealthy behaviours can spread through networks. Thompson and her colleagues are also interested in the positive side: whether social relationships can be used to support healthier behaviour.

One ongoing project in Amsterdam brings people together to eat once a week. The intervention combines healthy eating with social connection and investigates whether this could change dietary choices. The project is still under way, so it is too early to claim an effect. But it reflects a broader shift in thinking: an intervention does not necessarily have to target individuals one by one. It can also change the social environment in which choices are made.

Earlier research by Thompson and colleagues provides an indication of why this matters. Using data from the northern Netherlands, they found that people with a vegetarian among their close social ties were more likely both to become vegetarian and to maintain that diet over time. A personal intention, in other words, may be easier to sustain when the surrounding network supports it.

Effective health interventions and policy require action beyond the healthcare sector, addressing the social, economic, and environmental conditions that shape health. Here, there is reason for optimism: Thompson sees growing recognition that improving health requires coordinated action across different policy domains.

This is also where social sciences have a distinctive contribution to make. Health is biological, but the conditions that produce health are also economic, social, behavioural, political and environmental. Understanding why inequalities persist therefore requires research into how people live, how resources are distributed, how communities function and how policies interact over time.

That is one of the ambitions behind the new 'Social Sciences Human Health Hub' at Wageningen University & Research: to connect expertise that is often separated by discipline or policy domain and to study health as the outcome of interconnected systems.

The challenge is not simply to help people make healthier choices. It is to create environments in which healthier lives become possible for more people. And that changes the question policymakers need to ask. Not only: how do we improve healthcare? But also: what is happening in people’s homes, schools, neighbourhoods, workplaces and social networks long before they ever enter a consulting room?